Field of the Invention
The present invention relates to a lens barrel and an optical apparatus.
Description of the Related Art
Conventionally, a lens barrel which is used as an interchangeable lens in an optical apparatus such as a digital still camera, a video camera, or the like has a mechanism by which a lens (optical element) is movable therein in the optical axis direction. For example, in such a moving mechanism, in order to suppress the occurrence of engagement backlash, rollers each of which rotates about an axis orthogonal to the optical axis and is urged by spring are provided at two positions equally arranged by 120 degrees as viewed from the optical axis direction on the outside of a moving group for holding a lens. Likewise, rollers are also provided at two other cross-sectional positions spaced apart in the optical axis direction. With the aid of such a structure, the roller is pressed against a fixed barrel at the outer periphery side of the moving group, resulting in suppressing the occurrence of backlash which may occur during movement of the moving group. Japanese Patent Laid-Open No. 2009-31424 discloses a lens barrel in which a first moving frame serving as an outside moving frame and a second moving frame serving as an inside moving frame for holding a lens are held by four rollers each of which is urged by spring and rotates in association with a relative movement between these moving frames.
However, in the technique disclosed in Japanese Patent Laid-Open No. 2009-31424, if some impact is applied to the entire lens barrel, the offset of the roller occurs in a direction orthogonal to the optical axis, i.e., the offset of the roller occurs at the central position of the optical axis of the first moving group, resulting in an adverse effect on optical performance. In addition, in the technique disclosed in Japanese Patent Laid-Open No. 2009-31424, the area of contact by a roller surface of the roller is small, and thus, dents may be formed on the contact surface on the outside fixed barrel side when the above impact is applied to the entire lens barrel. The dents cause the roller to displace in an unintended direction during normal movement of the moving group, which is not preferable because of the occurrence of movement of an imaging screen or a projection screen, i.e., an image shake phenomenon.